Kevin Drum shows the following graphic (link) to illustrate where the House stood on authorizing force in Syria.
What interests me is whether the semi-circle concept adds to the chart. It evokes the physical appearance of a chamber, presumably where such a debate has taken place -- although most televised hearings tend to exhibit lots of empty seats.
The half-filled circles in particular do not make peace with me.
Here is a tree map of the same data.
Notice that legend boxes are unnecessary.
A pie chart with appropriate labeling acts similarly.
A profile chart produces mixed results:
This version has the advantage of stacking the voting variable. It doesn't do a good job describing future scenarios.